# Statistics

Paper instructions:
A clinical psychologist wants to determine whether group therapy sessions are effective in treating anxiety disorders. He has 20 clients from a therapy group complete an anxiety inventory where higher scores indicate increased levels of anxiety and compares their scores to published norms for the general population. To answer the psychologist’s question, we can set it up as a hypothesis testing problem and use the data collected to answer it. Complete the following to show how this would be done. (1 point each)
What statistical test would be appropriate in this case? Explain the rationale for your answer.

State the null and alternative hypotheses in words.
State the null and alternative hypotheses in statistical symbols
Would the test be right-tailed, left-tailed or two-tailed? Explain the rationale for your answer.
Describe a potentially confounding variable and explain how that might affect the conclusions from the study.

Question

2 of 5
A health psychologist wants to determine whether children who eat breakfast perform better on school work than children who do not have a breakfast meal. She gathers two groups for her comparison, 15 children who have a normal breakfast meal and another 15 who do not have breakfast, on a day when they have a math test scheduled in the mid-morning at school. The psychologist plans to use scores on the math test as an indicator of school performance. Respond to the prompts below. (1 point each)

What statistical test would be appropriate in this case? Explain the rationale for your answer.
Identify the independent variable in this study.
Identify the dependent variable in this study.
Describe a potentially confounding variable and explain how that might affect the conclusions from the study.
State the null and alternative hypotheses in words.

Question

3 of 5
A recent study by a team led by Dr. Stanton Siu, M.D., of Kaiser Permanente reported a finding that heavy alcohol consumption was associated with an increased risk of developing lung cancer. Respond to the prompts below. (1 point each)

Would it be appropriate to conclude from this that heavy drinking causes lung cancer? Explain the rationale for your answer.
Propose an alternative explanation for the results. I.e., how else might you account for the observed association between alcohol consumption and lung cancer?
If you were to calculate a correlational coefficient for two variables and it turned out to be -1 (minus one) how would you interpret this relationship? I.e., what is the relationship between the two variables?
How would you interpret the coefficient of determination for the outcome described above where the r value was determined to be -1?
Would it be appropriate to conclude that the variables in the two questions above, where r was determined to be -1, are causally related? Why or why not?

Question

4 of 5
A social science researcher notes that in a population of psychiatric inpatients the ethnic mix seems out of balance with what she has understood to be the ratios in the general population. Respond to the prompts below to show how she might determine whether the inpatient ethnic mix varies from the mix in the general population. (1 point each)

What statistical test would be appropriate to use here? Explain the rationale for your answer.
What assumptions would need to be met in order to use the test?
Describe the data that the test would be based on as either quantitative or qualitative. Explain the rationale for your answer.
Write an example of how the null and alternative hypotheses for this test could be stated.
What would the researcher need to know in order to calculate the appropriate test statistic? I.e., what values need to be known or calculated in order to complete the calculation of the test statistic?

Question

5 of 5
In a paragraph or two, please provide some insight into how you might put your new knowledge and skills to use in your present or future work, or how it might support additional education or training you plan to complete. (5 points)

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